1. Field of the Invention
The present invention relates to locking devices. More particularly, the invention is a lock for securing flange junctures such as in piping systems.
2. Description of Related Art
In industries such as the chemical industry and the oil and gas industry, it is common to join pipes to each other or to another element such as a valve or storage tank connection. This type of equipment may be quite valuable or the liquid or gas stored or transported are valuable. It is generally impractical to monitor this equipment to deter thieves or to avoid the accidental separating of the flanges. An apparatus to lock the flanges together would be desirable. The apparatus would desirably be amenable to repeated locking and unlocking, and be simple and compact in design for carrying purposes, and be rugged and reliable for outdoor use.
U.S. Pat. No. 4,366,970, issued Jan. 4, 1983, to Hogan, Jr., describes a clam shell closure which fits over the flange juncture to prevent external access to the holding bolts of the flange juncture. The ""970 patent requires welding of the clam shell closure together, making a relatively permanent flange juncture, and making disassembly and reuse-difficult.
U.S. Pat. No. 1,473,751, issued Nov. 13, 1923, to Walker, describes a lock for a water meter comprising a bar with a T-shaped head that fits through slots in pairs of nuts that fit over the inlet and outlet junctions on opposite sides of the water meter. Once the bar is placed through the slots on the nuts, a lock may be placed through an aperture in the end of the bar. The lock of the ""751 patent requires special nuts and their correct alignment which would be impractical for industrial use.
U.S. Pat. No. 725,290, issued Apr. 14, 1903, to Speer, describes a hinged locking device that fits over a coupling of a pipe. A lock secures the device in place. The ""290 patent is a clamshell device enclosing the entire coupling and, thus, is heavy and bulky to carry and assemble, particularly for large flanges.
U.S. Pat. No. 4,571,966, issued Feb. 25, 1986, to Lopez, Jr., describes a locking mechanism that incorporates pipe flanges having locking receptacles through which extends a retaining sleeve threadedly received thereby and secured by means of a locking ring. The ""966 patent requires a special flange, and, thus, it would be impractical in normal industrial use.
U.S. Pat. No. 4,541,256, issued Sep. 17, 1985, to Green, describes a flange lock for preventing unauthorized access to flange junctures such as on pipe connections. As in the ""290 patent discussed above, the ""256 patent is a clamshell device enclosing the entire coupling and, thus, is heavy and bulky to carry and assemble, particularly for large flanges.
U.S. Pat. No. 5,950,462, issued Sep. 14, 1999, to Neeley, describes various embodiments of devices for locking out a valve, i.e., preventing its unauthorized opening or closing. Among these devices is a scissors-like bail having aligning holes to accept a padlock. The locking device of the ""462 patent would not be useful in locking flange junctures.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The present invention is a lock for isolating and securing a flange juncture. The flange lock has two identical approximately L-shaped parts, each with a circular nut or bolt cover mounted to a support neck forming one end portion of a shaft having a series of holes along the shaft leading to a free end, the holes being of such size as to accommodate a lock such as a padlock, and a shaft receiver attached to the support neck forming a slot to receive the shaft of the other L-shaped part. The circular covers fit over a nut and bolt on the opposite sides of the joined flanges while a lock, such as a padlock, secures the shafts together. Each cylindrical cover has a partial end cap which allows the threaded portion of a bolt to extend through and beyond the cylindrical cover while blocking insertion of the socket of a wrench in any attempt to engage the bolt head or nut for removal without unlocking the padlock.
Accordingly, it is a principal object of the invention to provide a locking device for flange junctures.
It is another object of the invention to provide a locking device as above which surrounds a flange juncture joined by a bolt head, nut, or stud and corresponding nuts threaded on the bolt.
It is a further object of the invention to provide a locking device as above which is adjustable for different thicknesses of flanges.
Still another object of the invention is to provide a locking device as above having two identical interlocking elements which slidingly engage each other.
Yet another object of the invention as above, each element having a shaft with a plurality of bores centrally located therealong so as to allow the adjustment of length by sliding said shafts relative to each other such that when the bores align a padlock may be inserted therethrough.
It is still another object of the invention to provide a flange juncture locking device that may be easily and repeatedly installed and removed from the flange juncture.
It is yet another object of the invention to provide a flange juncture locking device which is relatively light in weight, compact, and easily carried by an installer.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable, and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.